What color wing to use? I suggest using the color that best matches the bottom/sand where you are fishing. I found that my darker Keys flies were useless as the sand in our area was an almost white beige. We also discovered, at low tide, the flats were covered with this color crabs just larger than a US dime. We moved to size 6 and 8 flies and had much more success. Match the hatch! Just like when fishing a new stream and turning over rocks to assess insect life to match, spend some time on the flats determining the color and size of the prey and your luck will increase.